The flue gas carbon fixation by seawater decalcification method,not only soften seawater seawate and deal with flue gas,but also can obtain pure calcium carbonate as by-products through process control,achieving “turning waste into treasure”.With seawater and simulated flue gas as raw materials and magnesium oxide as regulator,gas-liquid contact and continuous operation were realized by bubbling way and calcium carbonate aragonite was prepared as well.The effects of factors,such as magnesium ion concentration,temperature,liquid level,concentration of surfactant sodium dodecylbenzene sulfonate（SDBS）,on the purity,particle size and morphology of solid products were investigated.The solid products were characterized by SEM,XRD,FT-IR and Mastersizer 2000.The results of the study indicated that pure calcium carbonate aragonite can be obtained with the minimum average particle size of 11.729 μm.Increasing temperature and liquid level were likely to cause larger aggregates.And the average particle size of the products increased with the increasing of SDBS concentration.